The Train Speed Optical Illusion

If you watch the video above of a front-facing camera on a moving train, the train appears to move much faster in the zoomed out view than in the zoomed in view. Here’s what’s going on:

The illusion that speed decreases when zoomed is “because when one focuses on an inner portion of the movie, the optic flow angular speed is slow, and appears to fill one’s entitle visual field, which is consistent with overall lower forward speed.

Note: The more zoomed, the more densely packed the overhead rigging appears. So, even though you appear to be moving forward more slowly when zoomed in, the actual rate of rigging flowing by remains constant, consistent with same forward speed in all conditions.

(via the kid should see this)

• optical illusions
• video